Swirler for use with burners of the gun type



Nov. 5, 1968 E, L. OEHLERKING 3,409,231

SWIRLER FOR USE WITH BURNERS OF THE GUN TYPE Filed Jan. 23, 1967 INVENTORS ERWIN L. OEHLERKING ATTORNEY United States Patent SWIRLER FOR USE WITHBURNERS 0F THE GUN TYPE Erwin L. Oehlerking, 9798 Oak, Des Plaines, Ill. 60016 Filed Jan. 23, 1967, Ser. No. 611,038 1 Claim. (Cl. 239406) A swirler having a plurality of vane-like blades extending from a support ring and characterized by maximum air flow between the blades adjacent the periphery thereof and by minimum air flow at the support ring to supply minimum air flow at'the support ring, so that'minimum air is supplied at 'afuel nozzle at the center of the support ring to prevent dancing of the flame pattern toward and away from the fuel nozzle. 1

Prior art swirler devices of the kinds as shown in Sanborn Patents Nos. 2,976,919 and 2,976,920 and Keyes et al. Patent No. 3,258,057 have all been directed to structures for supplying air at the burner nozzle to propagate the flame thereat, and to complete the burning by providing a swirling envelope of combustion air about the propagated flame to complete the combustion of-the fuel.

Such prior art devices have been formed from a stamping requiring blanking arid forming'operations and special support arrangements to give particular direction of the air at the fuel nozzle for initial flame propagation.

The swirler according to the present invention is preferably formed in a single blanking and forming operation, and the fan-like blades extending from the support ring are each defined by identical arcs along which the blank is sheared during the blanking and forming operation, each fan-like blade being defined by these arcs and presenting a blade portion directed toward the air current in the burner tube and an integral blade portion extending in the direction of the air current. The configuration of the fan-like blades is such as to provide an area of flow between adjacent blades which decreases from a maximum at the periphery to a minimum near the support ring, so as to provide minimum air to the flame emerging at the fuel nozzle to prevent dancing of the flame pattern toward and away from the nozzle.

With the foregoing considerations in mind, it is a principal object to provide an improved swirler for a gun type burner for providing proper combustion air at the fuel nozzle for proper flame propagation and initial combustion thereat, and additional combustion air in a vortex at points spaced from the fuel nozzle to complete the combustion.

Another object is to provide a swirler which will supply a minimum quantity of air to give good preliminary burning and flame propagation at the fuel nozzle, so that there is no dancing of the flame toward and away from the nozzle, toward the end that there is no pulsation of the flame longitudinally of the axis of the burner gun.

In the drawing:

FIG. 1 is a longitudinal sectional view through the burner tube of a gun type burner, showing the improved swirler according to the present invention;

FIG. 2 is a view similar to FIG. 1 showing details of mounting the swirler on the fuel supply pipe;

FIG. 3 is a front view of the swirler looking in the direction of the arrows 33 of FIG. 2;

FIG. 4 shows the path of the air supplied at the fuel nozzle to give initial propagation of the flame at the fuel nozzle;

FIG. 5 shows the manner in which the swirler may be constructed from a flat sheet stock; and

FIG. 6 is a graph showing the gradient of the air volume supplied by the swirler as the air volume varies from the periphery thereof towards its center at the fuel nozzle.

The improved swirler according to the present inven- 3,409,231 Patented Nov. 5, 1968 2 tion is denoted by the reference numeral 10 and is shown in situ with respect to a burner tube 11, the forward end of which extends a short distance through an opening 12 in a wall 13 of a combustion chamber 14. A flange'16 secured to burner tube 11 abuts the wall 13 and limits the position of burner tube 11 in combustion chamber 14.

A supply pipe 17 is supported within burner tube 11, and is connected to a supply 'pipe'18 by an elbow coupling 19. Fuel is supplied by the pipe 17 to a burner nozzle 21, the precise form of which forms no part of the present invention, except to say it can supply either liquid fuel such as furnace oil, or gaseous fuel under pressure.

As seen in FIGS; 2 and 3, the swirler 10 has a series of fan-like blades 22 which extend radially from an inner flat support ring 23 having a central circular opening'24 through which the burner nozzle 21extends. A split ferrule 26 for supporting the swirler 10 on the nozzle 21 has a base flange 27 which is welded or otherwise secured to the upstream face of the support ring 23. Ferrule 26 is clamped about a barrel 28- of the nozzle 21, and has a pair of spaced ears 29 struck out therefrom, the cars 29 being clamped by a through bolt 31 to hold ferrule 26 and swirler 10 in place on the barrel 28.

The swirler 10 is held in position against a lip flange 32 on the burner tube 11.

An ignition structure is provided for the burner nozzle 21, and as seen in FIGS. 1 and 3, such structure comprises an ignition electrode 33 guided and supported in an insulating sleeve 34. Ignition electrode 33 extends between adjacent fan-like blades 22 in spaced relationship to the flat support ring 23 and in close proximity to the burner nozzle 21. As is conventional in such ignition devices, a potential exists between the insulated electrode 33 and ring 23 to strike an arc igniting the fuel discharged at the burner nozzle.

The insulating sleeve 34 is supported in a tubular housing 36 secured by a clamp 37 to supply pipe 17. Alternately, the ignition structure consists of a pair of electrodes spaced angularly of each other and extending between the fan-like blades 22. In such cases the potential exists across the two electrodes rather than between an electrode and the ring 23.

The swirler 10 is formed in a unique manner so as to give the aforemetnioned characteristics, and the same is constructed as seen in FIG. 5, which shows a circular blank B having the central opening 24 therein. The fanlike blades 22 are laid out on the blank B by equiangularly spaced rays R. A base circle BC corresponding to the outer diameter of the support ring 23 is constructed on the blank B. An are A is struck from each ray R with a center AC on ray R, each such arc A being tangent to the base circle BC substantially where it cuts the ray R.

A blanking and forming die, not shown, is adapted to shear the blank B along the arc A and to twist each fanlike blade 22 formed in the use of such die along a ray R which intersects the arcs A substantially at their inner ends. It is known to those skilled in such operations that the swirler 10 may be formed thusly in a combined blanking and forming operation in a single die from a strip of flat stock.

The finished swirler seen in FIG. 3 thus provides areas of flow for a current of air in the burner tube 11 and through the swirler 10 which vary from a maximum at the periphery of the swirler to a minimum at the periphery of the inner support ring 23. These varying areas of flow between the fan-like blades 22 are denoted by the letters D D and D At the minimum area of flow where the blades 22 have their roots, only minimal air is supplied to the burner nozzle 21. Such minimum supply of combustion air has the property of providing sufiicient air for initial flame propagation, but not in such quantity to cause dancing of the flame toward and away from the burner nozzle. Such minimal area of air can be described as having a vorticial configuration IV.

On the other hand, the combustion air supplied through the swirler 10 where the areas of flow are larger, can be described as moving in an outer vorticial path 0V. This outer and larger supply of air completes the combustion of the fuel in the flame initially propagated within the inner vortex IV.

As seen in FIG. 6, air passing through the swirler 10 has a volume gradient from the maximum at the periphery to a minimum at the support ring 23.

The configuration of the fan-like blades 22 as defined by the arcs A is such as to provide blade portions 22A extending in a direction opposed to the direction of flow of air in burner tube 11, and blade portions 22B extending in a direction corresponding to such direction of flow.

In the blanking and forming operations the blades 22 have the same pitch, but the pitch may vary from 35 to 50.

It may be noted that the swirler 10 can also be formed in a casting operation, rather than by stamping.

I claim:

1. A swirler for use with a burner of the gun type wherein air blows forwardly in a burner tube to a combustion chamber and past a fuel discharge nozzle, said swirler being adapted to be supported transversely in said burner tube adjacent said discharge nozzle, said swirler being circular in configuration and comprising an inner flat ring having a central opening therein for said discharge nozzle, a plurality of fan-like blades formed integrally with said inner fiat ring and extending radially therefrom, each of said fan-like blades being defined by a pair of identical arcs having the center of each lying on a ray which is equiangularly spaced from an adjacent ray, each of said arcs extending from the periphery of said swirler to a point at its inner end substantially tangent to said inner flat ring, each of said fan-like blades being twisted along another ray passing substantially through the point defining said are at its inner end, the area of air flow between adjacent blades decreasing from a maximum at the periphery to substantially zero area of flow at the periphery of the fiat ring to supply minimum air to the flame emerging at the center of said flat ring to prevent dancing of the flame pattern toward and away from said nozzle.

References Cited UNITED STATES PATENTS 2,485,244 10/1949 Sanborn 239-405 3,258,057 6/1966 Keyes et al 158l.5 X

FREDERICK L. MATTESON, JR., Primary Examiner.

E. G. FAVORS, Assistant Examiner. 

1. A SWIRLER FOR USE WITH A BURNER OF THE GUN TYPE WHEREIN AIR BLOWS FORWARDLY IN A BURNER TUBE TO A COMBUSTION CHAMBER AND PAST A FUEL DISCHARGE NOZZLE, SAID SWIRLER BEING ADAPTED TO BE SUPPORTED TRANSVERSELY IN SAID BURNER TUBE ADJACENT SAID DISCHARGE NOZZLE, SAID SWIRLER BEING CIRCULAR IN CONFIGURATION AND COMPRISING AN INNER FLAT RING HAVING A CENTRAL OPENING THEREIN FOR SAID DISCHARGE NOZZLE, A PLURALITY OF FAN-LIKE BLADES FORMED INTEGRALLY WITH SAID INNER FLAT RING AND EXTENDING RADIALLY THEREFROM, EACH OF SAID FAN-LIKE BLADES BEING DEFINED BY A PAIR OF IDENTICAL ARCS HAVING THE CENTER OF EACH LYING ON A RAY WHICH IS EQUIANGULARLY SPACED FROM AN ADJACENT RAY, EACH OF SAID ARCS EXTENDING FROM THE PERIPHERY OF SAID SWIRLER TO A POINT AT ITS INNER END SUBSTANTIALLY TANGENT TO SAID INNER FLAT RING, EACH OF SAID FAN-LIKE BLADES BEING TWISTED ALONG ANOTHER RAY PASSING SUBSTANTIALLY THROUGH THE POINT DEFINING SAID ARC AT ITS INNER END, THE AREA OF AIR FLOW BETWEEN ADJACENT BLADES DESCREASING FROM A MAXIMUM AT THE PERIPHERY TO SUBSTANTIALLY ZERO AREA OF FLOW AT THE PERIPHERY OF THE FLAT RING TO SUPPLY MINIMUM AIR TO THE FLAME EMERGING AT THE CENTER OF SAID FLAT RING TO PREVENT "DANCING" OF THE FLAME PATTERN TOWARD AND AWAY FROM SAID NOZZLE. 